Solar-powered
machine could let astronauts make their own water and oxygen
from MOON ROCKS

Solar-powered machine could use lunar soil
collected by robots on the moonIt would extract water from the soil, then obtain
oxygen with further processingIt would only require oxygen from Earth at start,
cutting down payload weight

By Cheyenne Macdonald

An aerospace engineer has developed a solar reactor that could
allow astronauts to make their own water and oxygen on the moon.

The system can extract water from lunar soil, and would only
require hydrogen brought from Earth for its initial use – after
the first few hours, hydrogen would be recycled from then on.

As hydrogen is far lighter than oxygen, the system could
dramatically cut down on the weight of a mission to the moon.

The machine has now completed a six-month test run, and according
to the creator, it could make enough oxygen and water to supply up
to eight astronauts.

The solar-powered system can extract water from lunar soil, and
would only require hydrogen brought from Earth for its initial use
– after the first few hours, hydrogen would be recycled from then
on.

THE NEW MACHINE

The process uses the iron-titanium oxide ilmenite (FeTiO3),
which is found in the ‘dark’ areas of the moon.

This could be dug up by a lunar robot, and carried over to the
reactor, according to Denk.

Lunar soil, unlike soil on Earth, does not experience weathering,
as the moon does not have an atmosphere.

So, the particles are oddly shaped and have jagged edges.

Before use, they would need to be pre-treated to smooth them out,
then sieved to obtain the right grain size.

And, it would only require hydrogen brought from Earth for the
initial processing.

Afterwards, this would be recycled.

According to Denk, the machine can process a 25kg particle load in
under an hour.

In just one hour, it can make 700kg of water – and, in four hours,
it could produce 2.5 kg of oxygen, all using under 10 kW of
electricity.

Researchers have been working for decades to come up with ways to
make oxygen on the moon.

‘From the beginning people were thinking this probably has to be
done with a solar furnace, because on the moon there is not very
much to heat a system that you can use; photovoltaics with
electricity or a nuclear reactor or concentrated solar radiation,’
said Thorsten Denk, who worked on the device for 10 years at the
Plataforma Solar de Almeria (CIEMAT).

‘After the Apollo missions, scientists had a lot of ideas of how
to make oxygen on the moon, because every material that you bring
from Earth costs money.

‘For every kilogram of payload you need hundreds of kilograms of
fuel.’

Denk’s reactor can split water from the lunar soil, which can then
be further split into oxygen and hydrogen.

And, the machine he’s built is the real size of what could be
built on the moon to support a crew of 6-8 people.

It currently weights 400 kilograms, but could be reduced with
further refinement, Denk says.

‘The hydrogen would be just for the first few hours. Then that
would be recycled with the electrolyzer,’ he explained.

‘Even if you bring hydrogen from Earth and get oxygen from the
Moon for making rocket fuel, you save nearly 90% of the weight.

‘Hydrogen is the lightest element. Oxygen is much heavier.’

The moon experiences long periods of sunlight, followed by long
periods of darkness - and, the conditions are ‘ideal’ for making
solar fuel, according to Denk.

‘Daylight is 2 weeks without interruption, and then you have the
same half-month of dark as night. So if you need three hours to
turn it on, it's not a big problem,’ Denk said.

‘There is no atmosphere on the Moon, and there is no weather, no
clouds, so you really can operate from sunrise to sunset at full
power for each half-month.’

Solar furnaces require very high temperatures – but, they can’t be
too high as to make the lunar soil ‘gum up’ and stick together, in
what’s known as sintering, the creator explain.

‘The chemical reaction starts to be working from 800°C but
sintering starts to be a problem at 1,050°C degrees, so my goal
was not to surpass the 1000°C,’ he explained.

‘I achieved a bit more than 970°C and the maximum was hardly above
1000°C.

‘So I had a temperature in the bed of not more than 30° up and
down, for the highest possible average temperature without
sintering.’

Upscaling of a SolarPowered
Reactor for CO2-free Syngas and Hydrogen Production by Steam
Gasification of Petroleum Coke

Thorsten Denk, et al.

US2011232635CONCENTRATED SOLAR RADIATION ASSEMBLY

Radiation receiver incorporates a radiation entry window which is
installed into the boiler wall in such a way that mechanical
stresses in it are reduced by its displacement relative to the
boiler wall

BACKGROUND OF THE INVENTION

[0001] This invention relates to a solar energy concentrating and
collecting assembly, that is to closed central assembly systems
for concentrated solar radiation, even more particularly, to a
refrigerated window for a large-scale concentrated solar radiation
assembly or structure.

[0002] Concentrated solar power systems focus direct solar
radiation through optical devices onto an area where a assembly is
located. The assembly transforms the radiation into heat. Since
concentrated solar power systems produce both heat and
electricity, they can replace all or part of the energy
requirements in some industrial applications. On the small scale,
they also have durability and low operating costs.

[0003] Various solar energy collection arrangements are known.
Many utilize an assembly with a receiver located at the focus. The
receiver or central solar radiation assembly absorbs concentrated
sunlight at high temperatures, commonly about 700°-1500° C. and
transfers the heat generated by the solar absorber to a working
fluid, which either serves as a heat carrier fluid or is designed
to perform a thermochemical process. In one known kind of central
solar assembly, a so-called tubular assembly, the working fluid
flows inside tubes located usually near the inner periphery of the
solar assembly housing. In such a assembly, solar radiation is
absorbed at the outer surface of the tubes and is transmitted as
heat to the working fluid, which is thus heated. The overall
resistance to heat transfer and the ensuing heat loss in such
tubular central solar assemblys is relatively high.

[0004] High temperature closed solar assemblies generally have a
cylindrical housing. Closed solar assemblies are closed at one
side by a transparent window to form a sealed recipient capable of
holding a working fluid or a chemical reaction mixture in direct
contact with the absorber while avoiding physical contact between
the working fluid and the ambient air. The sealed recipient also
protects against temperature loss. In operation, the working fluid
or reaction mixture is forced to flow across the assembly chamber
whereby heat is transferred from the absorber to the fluid and is
utilized for the chemical reaction or is transported outside the
assembly.

[0005] The transparent window that shields the absorber in a solar
assembly must be capable of sustaining the extreme conditions of
high solar flux, high temperature and in some applications
pressure associated with the conditions of operation. Solar
assemblies designed for large-scale solar energy conversion
systems need large transparent windows. These windows with the
necessary dimensions and the required optical/thermo mechanical
qualities are not readily available. Since large pieces must be
made to order and the requirements concerning mechanical stability
increase with size, these windows are extremely expensive or even
impossible to manufacture. As a result, there is a need for
improved large-scale solar assembly windows and large-scale
concentrated solar power systems.

SUMMARY OF THE INVENTION

[0006] The primary object of the present invention is the creation
of an improved solar assembly window for a central solar assembly
that fulfills the requirements of a large central assembly in
terms of efficiency, thermal and mechanical loads.

[0007] It is a further object of the present invention to provide
a concentrated solar radiation assembly.

[0008] In accordance with the present invention, a large-scale
concentrated solar radiation assembly is disclosed. The
concentrated solar radiation assembly comprises a housing divided
into segments by housing trusses; window blocks positioned within
the segments supported by the housing trusses; and, internal
trusses positioned on top of the window blocks and within the
segments. The housing trusses and internal trusses are hollow and
define cooling channels for flow of cooling liquid, such as water
or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A detailed description of preferred embodiments of the
present invention follows, with reference to the attached
drawings, wherein:

[0015] The invention relates to a refrigerated window for a
large-scale concentrated solar radiation assembly or structure.
The window is divided into several segments that are shaped to
keep the assembly hermetically sealed. The hermetically sealed
assembly, including the window, is able to withstand thermal and
mechanical loads caused by the highly concentrated solar
radiation, very high temperatures, and the pressure difference
between the interior and the exterior. Outside trusses define the
shape of the window segments. Window segments are held within the
segments by a housing and the outside trusses. The outside trusses
apply the force needed to hermetically seal the assembly. In
addition, the outside trusses are shaped to resist mechanical load
and are water cooled to resist thermal load.

[0016] FIG. 1 depicts a non-limiting embodiment of the present
invention. FIG. 1 shows an exploded view of a large-scale
segmented refrigerated or water-cooled window assembly 20 for
highly concentrated solar radiation. Solar radiation enters from
the left of assembly 20 and the structure is on the right of
assembly 20. The window for a large-scale concentrated solar
radiation assembly or structure is divided into several segmented
window blocks 7, which can be made of glass, such as quartz glass,
or other suitable materials that are well known within the art.
Large-scale as used herein may be defined as an assembly having a
window where size makes durability of the window assembly an
issue, for example, where the window diameter or similar dimension
is larger than about 400 mm. In order to withstand the unavoidable
mechanical loads and to solve the fabrication problems associated
with larger sizes, the window is divided into several segments
that are refrigerated by liquid cooled trusses.

[0017] High mechanical load as defined herein is a function of
pressure difference and temperature level. Pressure differences of
2 bar, such as from ambient (1 bar) to 3 bar is considered a high
mechanical pressure load. Temperature above about 1000° C. is
considered high mechanical temperature load. The mechanical
pressure and temperature load can be increased up to an unknown
limit by reducing the spacing between the trusses and/or
increasing the thickness of the trusses and glass-blocks. In
theory, the window blocks of the present invention can handle
mechanical loads that reach beyond the practical limitations of
the window blocks, i.e. window blocks as big as football fields
may be manufactured to withstand high mechanical loads; however
depending upon their intended use, window blocks of such size may
not be practical.

[0018] Continuing on FIG. 1, the window blocks 7 are supported by
outer trusses shown here as horizontal and vertical housing
trusses 3. The horizontal and vertical orientation of the housing
trusses 3 helps to sustain mechanical load possibly caused by the
pressurized surface of the windows. An annular liquid-cooled
flange 1 is divided into segments 2 by the housing trusses 3. A
cooling liquid enters the housing trusses 3 through housing truss
liquid inlets 4. The cooling liquid, such as water, may be any
liquid that is well known within the art.

[0019] The housing trusses 3 are shaped to include a support
surface 5. The support surface 5 supports the window gaskets 6,
the window blocks 7 and an upstanding rib 8. Upstanding rib 8
provides support for the internal trusses 9 and spacing for the
window blocks 7. The internal trusses 9 are connected to the rib 8
of the external trusses 3 with countersunk screws 14. As shown in
FIG. 5, the window blocks 7 are captured between support surface 5
of the housing trusses 3 on one side and internal trusses 9 on the
other side. The countersunk screw 14 into upstanding rib 8 applies
sufficient force between housing truss 3 and internal truss 9 to
hermetically seal the window 7. The hermetic seal is also
effectuated by a soft ceramic material (not shown) between inner
truss 9 and window block 7. The soft ceramic material equalizes
the pressure on the window blocks 7 exerted by the support surface
5. The soft ceramic material may be any soft ceramic that is well
known within the art, such as ceramic fabric.

[0021] The solar radiation assembly of the present invention may
incorporate varying geometries. The differing assembly components,
including window segments as detailed above, may have differing
shapes,

sizes and/or orientation. For example, the window segments can be
round, square, rectangular and hexagonal. The corresponding
internal and external trusses may be orientated around the shape
of the window segments. Further, the window segments of the
present invention can be used in large-scale systems as described
above, and also in small-scale systems. The accompanying figures
and detailed disclosure are in no way limiting to the geometries
of the components that, as assembled, complete the solar radiation
assembly and/or structure of the present invention.

[0022] FIG. 2 illustratively depicts a non-limiting example of the
outside, solar radiation side, of the assembled concentrated solar
radiation assembly. This side of the assembly is exposed to solar
radiation, i.e. sunlight, which is collected through the window
segments 7. As depicted in FIGS. 2 and 3, there are a total of
twelve cooling water flows: one (3a) through each of the four
outer trusses 3; one (9a) through each of the four inner trusses
9; there are two through the flange 1 wherein one (1a) flows
through the upper half of flange 1 and one (1b) flows through the
lower half of flange 1; and finally, two (101 & 102) flow
through the curved outer trusses welded to flange 1.

[0023] FIG. 4 illustratively depicts a non-limiting example of the
inside, assembly/structure fluid side, of the assembled
concentrated solar radiation assembly. This side of the assembly
is not exposed to direct solar radiation. This side is exposed to
heat from the inside of the assembly.

[0024] The segmented refrigerated windows of the present invention
may be pieced together into an inexpensive large-scale solar
energy conversion system.

[0025] The resultant segmented refrigerated window for large-scale
solar assemblies/structures may be installed by any method, which
is well known within the art. The solar assemblies/structures of
the present invention are designed for large-scale solar energy
conversion systems; however, they may also be employed in
small-scale solar energy conversion systems. The segmented
hermetically sealed refrigerated windows may be created in an
unlimited amount of necessary dimensions. The shapes of the
components illustrated in FIGS. 1-4 are the preferred embodiments
of the present invention; however, regardless of the size or
shape, the solar assembly of the present invention is able to
withstand the optical load, thermal load and mechanical load
needed for large-scale concentrated solar radiation receiver
systems.

[0026] The large-scale concentrated solar radiation assembly
and/or structure of the present invention may be implemented in
other possible applications. The final physical and chemical
characteristics of the solar radiation assembly and/or structure
of the present invention may be applied to conventional energy
technology, renewable energy technology, industrial heat process
technology, conventional cementing technology, thermo chemical
process technology, and any application that may benefit from the
energy or heat generating properties of the present invention.

DE4336503 Apparatus and process for carrying out endothermic
chemical reactions

In order to create an apparatus for carrying out endothermic
chemical reactions involving participation of particles,
comprising a reaction vessel in which the particles can be heated
by electromagnetic radiation, in such a manner that an optimised
matching of the absorbed radiation power to an essentially
complete gasification of the carbon-containing material is
possible, it is proposed that the reaction vessel has a heating
zone in which absorber particles or absorber particles and the
particles can be heated by direct absorption of the radiation and
that the reaction vessel has a delay zone in which the absorber
particles give off heat to the particles in order to maintain the
chemical reaction.

The invention relates to a device for carrying out endothermic
chemical reactions involving particles, comprising a reaction
vessel in which the particles can be heated by electromagnetic
radiation.

In the context of research projects, for example, the gasification
of oil shale using electromagnetic radiation as a carbonaceous
material in stationary fluidized beds on a laboratory scale was
studied, the fluidized bed apparatuses were irradiated from the
outside.

The problem with these known solutions is that they are less
efficient on an industrial scale.The invention is therefore based
on the object to provide a device of the generic type, in which an
optimized adaptation of the absorbed radiation power to a
substantially complete gasification of the carbonaceous material
is possible.

This object is achieved in a device of the type described above
according to the invention that the reaction vessel has a heating
zone in which absorber particles or absorber particles and
particles can be heated by direct absorption of the radiation and
that the reaction vessel has a residence zone in which the
absorber particles heat to the Particulate to sustain the chemical
reaction.

The solution according to the invention is thus to be seen on the
one hand to absorb the radiation in a suitable manner and on the
other hand then to make the heat so long available to the
particles that they are capable of the best possible chemical
reaction.

The advantage of the solution according to the invention is in
particular the fact that on the one hand in the heating zone,
heating of absorber particles or absorber particles and particles
takes place and then the stored heat in the absorber particles is
a sufficiently long time available to the endothermic reaction
process with the particles sufficient To provide large amount of
heat available and thereby achieve a substantially fully
continuous reaction with the particles.

The heating zone can be designed differently. For example, it
would be possible to convey the absorber particles over a
horizontal distance in the heating zone.

However, it is particularly advantageous if the heating zone has a
falling section through which the radiation passes for the
absorber particles or the absorber particles and particles. The
advantage of a heating zone formed in this way is the fact that
the particles fly freely through the drop zone and thus there is
no need to keep the particles strongly heating up in the heating
zone in thermal contact with a complex, temperature-resistant
conveyor and thus lose heat.

In principle, it would be in the case in which absorber particles
and particles pass through the heating zone, conceivable to lead
them so that they separated, that is, for example, in the form of
separate case stretch the heating prevail.

However, it is particularly advantageous if the particles and the
absorber particles mixed with each other pass through the heating
zone and thus before the heating of both the absorber particles
and the particles, a mixing thereof, so that after the heating
zone in a simple manner, without further measures, the further
reaction the particles in the residence zone due to the uniform
mixing with the absorber particles can be done.

Preferably, mixing of the absorber particles and the particles is
achieved in that the absorber particles and the particles are
mixable in a mixing zone arranged upstream of the heating zone.
The mixing zone is preferably formed by a mixer which converts the
two free-flowing particle streams into one another.

In principle, the solution according to the invention could work
in such a way that the absorber particles and the particles or
residues thereof leave the reaction vessel together after the
residence zone.

It is particularly useful, however, if the absorber particles are
guided in the reaction vessel in a cycle through the heating zone
and the residence zone, since this eliminates the need to supply
large amounts of absorber particles through suitable locks, for
example, to the reaction vessel and remove it.

For this purpose, it is preferably provided that the absorber
particles can be brought to the heating zone from a discharge
following the dwell zone in a return conveyor device.

This feedback can be formed in various ways. For example, this
return conveyor can work mechanically. However, it is even more
advantageous if the return conveyor device works with a conveying
gas, because this avoids the problems of moving parts at high
temperatures.

Furthermore, it is provided in the case of working with conveying
gas return conveyor that the return of the absorber particles
leads to a separator which separates the conveying gas from the
absorber particles.

Preferably, the separator is arranged following the return
conveyor and produces a free-falling absorber particle layer.

In order additionally to achieve a preheating of the absorber
particles in the return conveyor, it is preferably provided that
the return conveyor is also heated by the radiation.
A particularly advantageous embodiment provides that the return
conveyor has a radiation absorber surface.

In theory, the radiation absorber surface could be arranged so
that it is acted upon separately from radiation, while at another
point in the reaction vessel, the absorber particles alone or as a
mixture with the particles are also exposed to radiation.

However, it is particularly advantageous if the absorber particles
or the absorber particles form an absorber curtain with the
particles in front of the radiation absorber surface of the return
conveyor device.

This absorber curtain is preferably selected to be so thin that
the radiation which does not impinge on the absorber particles or
particles strikes the radiation absorber surface of the return,
and heats the absorber particles returned in the recycling
so that no radiation energy is lost.

In the simplest case, the return conveyor is designed such that it
has a return duct whose front side facing the radiation forms the
radiation absorber surface at least in the heating area.

With regard to the formation of the dwell, no further details have
been given in connection with the previous explanation of
individual embodiments. Thus, an advantageous embodiment provides
that the residence zone is formed in the reaction vessel of
a dwell, this dwell is preferably designed so that it traps the
moving through the heating zone absorber curtain, formed from the
absorber particles or the absorber particles and the
particles.

Preferably, this dwell is designed so that in this the absorber
particles and the particles form a bed in which the absorber
particles and the particles are directly in preferably köperlichem
thermal contact with each other.

Alternatively, however, it is also conceivable to provide the
dwell zone as a further drop or conveyor line for absorber
particles and particles in which they move.

Since the residence zone constantly new absorber particles and
particles are supplied, it is necessary to remove them again from
the dwell zone.

For this purpose, preferably a discharge for the absorber
particles and the remainder of the particles remaining after the
gasification is provided.

In the case of an indwelling container in the simplest case, the
discharge is designed so that it forms a channel leading away from
this, preferably a channel following the direction of gravity.

Furthermore, in order to be able to feed absorber particles back
to the recycling device after the residence zone, a separator is
preferably provided downstream of the residence zone which removes
at least part of the residues of the particles after the chemical
reaction.

The particles can either themselves carry a substance that
undergoes an endothermic chemical reaction. However, it is also
conceivable that the particles themselves constitute a catalyst
which, when heated by the electromagnetic radiation, serves to
catalyze chemical reactions.

The solution according to the invention is particularly well
suited when the chemical reaction is a gasification reaction in
which a product gas is formed.

As materials for the particles, preference is given to
carbonaceous materials whose carbon is gasified.

A particularly advantageous embodiment of the solution according
to the invention provides that the absorber particles are ash
particles, for example gassed particles, so that no exact
separation between the residues of the particles and the absorber
particles is carried out, but the ash collecting in the dwell zone
is discharged to the same extent in the measure in that new ash is
formed in the residence zone, while the remainder of the ash
particles are passed as absorber particles via the return to the
heating zone where they heat up due to the radiation and then
transfer their heat to the particles in the residence zone, for
example to maintain the gasification process of the particles to
obtain.

In the solution according to the invention, for example, the
conveying gas for the absorber particles could be an inert gas.
However, this would have the disadvantage that the inert gas is
always in turn to be separated from the product gas produced
during the gasification of the particles.

For this reason, it is particularly advantageous if product gas is
used as conveying gas, so that no complicated separation between
the conveying gas and the product gas in the reaction vessel is
required, but a common discharge of product gas can be provided,
from which in turn conveying gas is recovered.

With regard to the heating zone, it has hitherto only been stated
that the absorber particles or the absorber particles and
particles are heated in this by electromagnetic radiation.
It is particularly advantageous, however, if the heating zone is
designed such that the absorber particles or particles and
particles passing through it directly absorb the solar radiation
reflected from the mirror systems to the reaction vessel. In this
case, can be obtained in a particularly simple manner from solar
radiation energy, namely the fact that they are reflected directly
from a mirror system or a large mirror array on the reaction
vessel and in the heating zone inside. Preferably, the mirror
system is designed so that it focuses the solar radiation on the
heating zone, wherein the size of the heating zone is dependent on
the focus.

In order to shield the heating zone against undesired external
influences and in particular also to make it possible to collect
the product gas in a simple manner, it is preferably provided that
the radiation enters the reaction vessel through a window so that
the interior of the reaction vessel is closed through the window.

In order to prevent the window from being contaminated by absorber
particles or particles which clog on it because of the high
temperatures, the window is preferably provided with a flushing
device which prevents settling of absorbent particles or particles
on an inner side of the window. In this case, especially the
provision of the fall distance in the heating zone proves to be
advantageous, since the purge gas requirement can be kept
significantly lower, in contrast to transported in a conveying gas
flow absorber particles and particles, since the turbulence is
lower.

Preferably, the flushing device is designed so that it generates a
flushing gas flow, which flushes the window on its side facing the
absorber particles or particles inside.

As purge gas, for example, an inert gas can be used. In order to
avoid a complicated separation of purge gas and product gas in
this case, it is advantageously provided that the purge gas of the
purge device, the product gas is used, so that this can be removed
again via the already provided for the reaction vessel product gas
removal.

Moreover, the invention relates to a method for carrying out
endothermic chemical reactions involving particles, in which in a
reaction vessel, the particles are heated by electromagnetic
radiation to run the chemical reaction. The object mentioned in
the introduction is achieved in a method of the aforementioned
type according to the invention in that the electromagnetic
radiation impinges in a heating zone, in which of these absorber
particles or absorber particles and particles are heated directly
by the radiation, and that provided on the heating zone following
dwell in which the heated absorber particles release heat to the
particles to sustain the chemical reaction.

Further advantageous embodiments of the method according to the
invention are already mentioned in connection with the
advantageous embodiments of the device according to the invention.

As materials for the material particles are preferably oil shale,
lignite, hard coal, biomass or similar materials used.

The temperatures in the heating zone are preferably more than 300
° C, more preferably more than 1000 ° C, depending on the nature
of the chemical reaction, in particular the gasification.

Further features and advantages of the invention are the subject
of the following description and the drawings of an embodiment.

In the drawing show:

Fig. 1 is a schematic representation of a gasification device
according to the invention; Fig. 2 is a longitudinal section through the reaction
vessel and Fig. 3 shows a cross section through the reaction vessel
along line 3-3 in Fig. 2nd

[ FIGURES NOT AVAILABLE ]
A designated as a whole with 10 embodiment of a gasification
device according to the invention comprises a solar collector
system 12, which reflects solar radiation in the direction of a
designated as a whole with 14 reaction vessel.

This reaction vessel 14, shown as a whole in FIG. 2, comprises a
thermally insulated housing 16 having a radiation window 18
arranged therein, through which radiation 20 focused by the solar
collector system 12 enters an interior of the reaction vessel 14.

In this case, the radiation 20 strikes an absorber curtain 24,
which drops over a drop section 22 due to the effect of gravity,
from absorber particles and material particles of the material to
be gasified. The absorber curtain 24 is heated while passing
through a heating zone 26 of the focused radiation.

The heated particles of the absorber curtain 24 pass after the
heating zone 26 in a residence zone 28, which is formed by a dwell
30. In this retention tank 30, the absorber particles and the
material particles of the material to be gasified are collected
and in thermal contact with each other, so that the absorber
particles have the opportunity to give off heat to the material
particles, so long as already begun in the heating zone 26
endothermic gasification reaction in the material particles can be
maintained until the material particles are substantially
completely gassed while absorbing heat from the absorber particles
substantially.

From the preferably designed as a thermally insulated container
retention tank 30 passes the mixture of absorber particles and
substantially gasified material particles via a standpipe 31,
which serves to compensate for the pressure conditions, to a
designated as a whole with 32 separator, in which by a gas supply
34, the absorber particles be promoted large part in a return
conveyor 36 and to a small extent to an ash removal 38th

The return conveyor 36 comprises a return channel 37 in which via
a conveying gas supply 40 additionally conveying gas is supplied,
which promotes the absorber particles from the separator 32 to a
separator 42 in the return passage 37. In this case, the return
channel 37 preferably runs, starting from the separator 32, along
a rear side 44 of the housing 16 opposite the radiation window 18
as far as the separator 42 arranged above the heating zone 26. In
the separator 42 there is a separation between the conveying gas
and the absorber particles, which form an absorber particle layer
48 falling down along a front side of the return channel 37 facing
the radiation window 18, which falls into a mixer 50 in which
material particles are added to the absorber particle layer via a
feed device 52 these are mixed so that the aforementioned absorber
curtain 24 exits the mixer 50 and also falls along the front side
46 of the return channel 37 via the drop section 22 through the
heating zone 26.

The front side 46 of the return channel 37 is formed in the region
of the heating zone 26 as a radiation absorber surface 54, which
in turn absorbed by the absorber curtain 24 not completely
absorbed radiation 20, contributes to a heating of the return
channel 37 in this area and thereby already preheating the in the
return channel 37 promoted absorber particles causes so that they
arrive already preheated in the separator 42.

As a result of the heating of the absorber particles and material
particles forming the absorber curtain 24, the gasification
reaction in the material particles begins already in the heating
zone 26 and product gas is produced. The gasification reaction
continues even after leaving the heating zone 26 and is still
maintained in the residence zone 28 by heat transfer from the
absorber particles to the material particles, so that in the
residence zone 28, the material particles gasify substantially.
The occurring product gas preferably exits from an absorber
curtain 24 receiving opening 56 of the retention tank 30 and flows
through the interior of the reaction vessel 14 to a arranged in
the bottom part 60 of the housing 16 Produktgasabfuhr 62nd From
the product gas removal 62, the product gas is fed to a particle
separator 64, preferably a cyclone, which separates remaining ash
particles from the product gas and then feeds the product gas to a
product gas buffer 66, preferably still cooling into a zone
provided between the particle separator 64 and the product gas
buffer 66 Radiator 68 is done.

Even before leaving the reaction vessel 14, the product gas is
cooled in a heat exchanger 70, which is arranged in the bottom
part 60, wherein the heat exchanger 70 has a heat exchanger
element 72 penetrated by the conveying gas to the conveying gas
supply 40, which already heat the product gas flowing off and the
discharged ash removes and heats the conveying gas to the feed gas
flowing 40 accordingly.

Product gas from the product gas intermediate store 60, which is
supplied to the heat exchanger element 72 via a compressor 74, is
preferably also used as conveying gas. Likewise, a compressor 76
is provided, which also compresses product gas from the product
gas buffer 66 and the gas supply 34 of the separator 32 supplies,
whereby this gas stream can be heated via a heat exchanger.

In addition, preferably, the gasification device according to the
invention is operated so that used as absorber particles in the
gasification of the material particles remaining ash particles are
used, so that automatically form after the gasification reaction
from the material particles absorber particles. In each case as
much ash is to be removed via the ash removal 38, that the amount
of absorber particles in the reaction vessel remains approximately
the same size.

As shown in FIG. 3, the radiation window 18 is further provided
with a free-purging device 80, which allows a purging gas film 82
to flow over an inner side of the radiation window 18 facing the
absorber curtain 24, in particular to keep the radiation window 18
free of the radiation window 18, in particular on its side facing
the absorber curtain 24 , wherein this purge gas film prevents the
adhesion of absorber particles or material particles on the inside
84 of the radiation window 18. This purge gas film 82 is fed via a
purge gas 86, which is also supplied by the compressor 76 or by an
additional compressor, so that product gas is also used as purge
gas. Again, a heating via a heat exchanger is possible.

The entire reaction vessel 14 is thus penetrated in its interior
only by product gas, on the one hand arises in this and on the
other hand supplied to circulate a defined amount of absorbent
particles in the circuit and on the other hand in the separator 32
to separate the resulting according to the supplied material
particles amount of ash and at the same time also to operate the
flushing device 80 for the radiation window 18.

Preferably, as shown in Fig. 3, the return passage 37 extends as
arcuate flat channel formed over the back 44 of the housing 16 and
engages with its Strahlungsabsorberfläche 54, the curved or flat
inside 84 of the radiation window 18, thereby characterized over
the distance of the radiation window 18th a homogenization of the
temperature is possible because each point of the radiation window
18 "sees" a large part of the radiation absorber surface 54 and
thus receives the thermal radiation from almost the entire area of
??the radiation absorber surface 54 and the absorber curtain 24,
so that a local and adverse overheating of the Radiation window 18
is avoided.

In addition, advantageously, the absorber curtain 24 is formed so
that always a predetermined fraction of the radiation 20 strikes
the radiation absorber surface 54, is absorbed by this and thus
leads to a defined heating of the funded by the conveying gas
through the return channel 37 absorber particles.

The curvature of the radiation absorber surface 54 also ensures
that the occurring radiation flux density of the radiation 20 over
the entire radiation absorber surface 54 is substantially
homogeneous.

In order to be able to start the gasification device according to
the invention without already produced product gas, an inert gas
reservoir 90 is preferably additionally provided, with which inert
gas of the conveying gas feed 40 can be supplied via the
compressor 74 for circulating the absorber particles. This inert
gas can also be used to flush the system.

The radiation receiver (10) comprises a pressurized boiler (12)
with a radiation entry window (18) which by means of a bearing
system is installed into the boiler wall (14) in such a way that
mechanical stresses in the entry window are reduced by
displacement of the window relative to the boiler wall.

[0001]
The invention relates to a radiation receiver, which comprises a
pressure vessel through which a working medium for energy
absorption from coupled into the pressure vessel radiation is
feasible, wherein the pressure vessel is provided with an entrance
window for the radiation.

[0002]
Such radiation receivers are also referred to as volumetric
radiation receivers.

[0004]
In the pressure vessel prevail in operation high temperatures of,
for example, 800 ° C to 900 ° C. It is intended to drive in the
future even at temperatures of the order of 1200 ° C or more. In
the pressure vessel working pressures of the order of 15 bar to 20
bar or more prevail.

[0005]
Due to the high pressures and temperatures during operation, the
entrance window is heavily loaded. In addition, a chemical load of
the entrance window through the working medium and other
substances may also occur.

[0006]
Based on this, the present invention seeks to provide a radiation
receiver, which works safely even at high pressures and
temperatures and has the longest possible maintenance intervals.

[0007]
This object is achieved according to the invention in the
radiation receiver mentioned above in that the inlet window is
mounted on a pressure vessel wall movable by means of a bearing
device that mechanical stresses in the entrance window by movement
of the entrance window relative to the pressure vessel wall are
degraded.

[0008]
High mechanical stresses in the entrance window, which is usually
made of quartz glass, arise from the fact that a
Fensterfußdurchmesser reduced when pressurized and the pressure
vessel wall thermally expands. Such changes in length may be on
the order of a few tenths of a millimeter. Furthermore, the
pressure vessel wall, on which the inlet window is mounted, can
buckle under pressure as well as by thermal expansion. As a
result, bearing surfaces of the entrance window on the associated
pressure vessel wall are no longer plane-parallel, which can cause
voltage spikes. Although glass usually has a high stability to
compressive stresses, but is less stable to tensile stresses. The
mechanical stresses that can build up in the entrance window due
to the described processes, can lead to a destruction of the
entrance window.

[0009]
Characterized in that the entrance window is mounted according to
the invention by means of a bearing device movable on the pressure
vessel wall so that mechanical stresses in the entrance window by
movement of the entrance window relative to the pressure vessel
wall are degraded, a stress build-up in the material of the
entrance window can be kept low or even largely avoided. By a
specifically set mobility of the entrance window thus the life of
the radiation receiver according to the invention is greatly
increased and corresponding maintenance intervals are increased.
The fact that the voltages in the entrance window are "degraded in
situ", the radiation receiver according to the invention can also
drive at high pressure and in particular high temperature. In
turn, the radiation receiver in a power plant can be specifically
adapted to, for example, a gas turbine; Gas turbines usually have
a nominal pressure at which the efficiency is optimized.

[0010]
From the prior art, it is known to weld to the entrance window a
glass flange, which serves to hold the entrance window to the
pressure vessel wall. The corresponding manufacturing process for
the entrance window is therefore complicated and expensive. When
operating the pressure vessel can be generated by deformations on
the glass flange mechanical stresses that can act as break germs.
According to the invention, because of the non-rigid mounting of
the entrance window on the pressure vessel, no glass flange needs
to be welded to the entrance window, so that in addition to the
more cost-effective production, the risk of breakage is further
reduced.

[0011]
It is particularly favorable if the entrance window is movably
supported by the bearing device transversely to an entrance window
axis. In this way, in particular tensile stresses can be reduced
in the entrance window; Glass has a reduced tensile strength
compared to compressive stresses.

[0012]
In a first embodiment of the device according to the invention the
mobility of the entrance window is ensured by the fact that the
bearing device has a sliding layer on which the entrance window is
mounted.

The sliding layer is a layer in which the sliding friction
coefficient is lowered, so that movement preferably takes place on
this layer. The sliding layer thus forms the defined location for
the mobility of the entrance window with respect to the pressure
vessel. In particular, it can be achieved that is destroyed by the
movement of the window by an otherwise undefined movement of the
window, a seal which seals the interior of the pressure vessel
from the outer space at the bearing of the entrance window.

[0013]
It is particularly advantageous if the sliding layer is arranged
between an end face of the inlet window and the pressure vessel
wall. As a result, a mobility and in particular mobility of the
entrance window can be achieved transversely to an entrance window
axis in order to be able to reduce mechanical stresses in the
entrance window.

[0014]
Conveniently, a seal is arranged between the sliding layer and the
inlet window in order to achieve a fluid-tight seal of the
interior of the pressure vessel with respect to the exterior
space.

[0015]
Advantageously, the seal is designed as a multi-layer seal. In
such a multi-layer seal can be achieved by the appropriate
arrangement and design of the layers high temperature resistance
and mechanical strength. In a preferred embodiment, the
multi-layer seal comprises graphite layers with metal foil liners.
The graphite layers, which in particular comprise precompressed
graphite, ensure the high temperature resistance and the high
sealing effect, and the metal foils, which are in particular thin
stainless steel foils, provide the mechanical strength.
[0]

It is particularly advantageous if the sliding layer is formed so
that it has a reduced coefficient of sliding friction for the
movement of the window. This prevents the entrance window slides
on the seal or slide in a multi-layer seal individual gasket
layers on each other. On the other hand, however, the mobility of
the entry window is secured with respect to the pressure vessel
wall, since just the sliding layer is provided.

For example, the sliding friction coefficient for the sliding with
sliding layer is about 0, 05th The coefficient of sliding friction
for the sliding friction of the entrance window on the gasket, the
sliding of the gasket on the pressure vessel wall (if no sliding
layer is provided) or for the sliding of gasket layers relative to
one another is usually of the order of 0.1. The sliding layer then
makes it preferable to slide on this same layer. This prevents the
seal from being destroyed. In addition, it is prevented that can
build up by an undefined slippage of the entrance window, for
example against the pressure vessel wall voltage spikes, which can
lead to breakage of the entrance window.

[0017]
In a variant of one embodiment, the sliding layer is formed by a
lubricant. This may be, for example, high-viscosity silicone
grease. Such a high-viscosity silicone grease has a coefficient of
sliding friction of the order of 0.05, has a good sealing effect,
good temperature, pressure, weather and chemical resistance and a
long service life under normal operating conditions of a
volumetric radiation receiver. It is also unlike normal fats free
of alkali metals and alkaline earth metals that could contaminate
the entrance window.

[0018]
It is favorable if a depot is provided for the subsequent delivery
of lubricant to the sliding layer. As a result, a
"self-lubrication" of the sliding layer can be formed, so that the
radiation receiver according to the invention has a long service
life, since lubricant losses can be compensated.

[0019]
In an alternative embodiment, the sliding layer is formed by a
low-friction coating of the pressure vessel wall.

[0020]
In a further embodiment, the storage device has a storage bed of a
deformable material in which the entry window is mounted.
Characterized a mobility of the entrance window is ensured in the
storage bed, wherein the entrance window is fixed simultaneously
in the storage bed. The storage bed with the storage bed material
can thus serve to fix the entrance window, to ensure its mobility
and to seal the interior of the pressure vessel from the outside.
In particular, no glass ring needs to be welded to the entrance
window as a retaining flange. As a result, a seal between the
interior and exterior space is ensured and in particular already
when the interior of the pressure vessel is depressurized.

[0021]
It is particularly advantageous if the bearing bed material is
elastically deformable. The elasticity of the bed material ensures
the mobility of the entrance window to reduce stresses and on the
other hand, a good fixation of the entrance window can be achieved
on the pressure vessel wall. In addition, the bearing bed material
due to its elastic deformability compensate for deviations of
bearing surfaces between the pressure vessel wall and the entrance
window, so that mechanical stress peaks are avoided or at least
reduced. Such stress peaks in non-plane-parallel bearing surfaces
can be caused by uneven thermal expansion, for example due to
inhomogeneous temperature distribution, by manufacturing
tolerances and / or introduced mechanical stresses. Local voltage
peaks can be so great that the breakage threshold of the entrance
window is exceeded. By the storage bed according to the invention
such spikes are compensated.

[0022]
It is particularly favorable if the storage bed material is
designed and arranged in the storage bed so that the shear modulus
is reduced transversely to the entrance window axis in comparison
to the modulus of elasticity parallel to the entrance window axis.
As a result, the mobility of the entrance window is ensured
relative to the entrance window axis, d. H. There may be a
relative movement between the entrance window and the pressure
vessel wall. This in turn can reduce mechanical stresses.

[0023]
One possible material for the bedding material is high temperature
silicone.

[0024]
It is favorable if the storage bed is arranged around an area of
??the entry window facing an interior of the pressure vessel and
an opposite area of ??the entry window facing an exterior space.
As a result, the entrance window is fixed in the storage bed and
secured the mobility in the storage bed for a relative movement
between the inlet window and pressure vessel wall.

[0025]
Furthermore, it is advantageous if the storage bed material is
arranged between one of the pressure vessel wall facing end face
of the inlet window and the pressure vessel wall. This makes it
possible to compensate for uneven bearing surfaces between the
inlet window and pressure vessel wall, which are caused for
example by uneven thermal expansions, by manufacturing tolerances
and / or by mechanical stresses. This in turn can avoid high
voltage spikes, which can lead to a breakage of the entrance
window.

[0026]
It is advantageous if the bearing bed is formed in a holding
element which is connected to the pressure vessel wall. The
holding element can be particularly rigidly connected to the
pressure vessel wall. The relative movement between the pressure
vessel wall and the entrance window and thus between the entrance
window and the retaining element is ensured by the bearing bed.
Conveniently, the retaining element is connected to the pressure
vessel, so as to provide a secure fixation of the entrance window.

[0027]
In an advantageous variant of an embodiment, a device for
measuring mechanical stresses is arranged in a foot region of the
entry window. It may in particular be one or more strain gauges.
It can then be read whether high mechanical stresses prevail in
the foot area of ??the entrance window. Such high mechanical
stresses may, for example, have their cause in that the lubricant
of the sliding layer has been consumed or the sliding layer has
been destroyed or that the relative movement between inlet window
and pressure vessel wall is limited in the bearing bed. The
tension measuring device then indicates that maintenance must be
performed. It can be prevented that build up in case of failure of
the bearing device with respect to the relative movement between
the inlet window and pressure vessel wall such high mechanical
stresses in the entrance window, leading to a break.

[0028]
It is particularly advantageous if the entrance window is fixed to
the pressure vessel by means of an elastic adhesive material. In
particular, no glass flange then has to be welded to the entrance
window with the disadvantages and problems already described. Due
to the elastic adhesive joint, the relative movement between inlet
window and pressure vessel wall is ensured at the same time.

[0029]
Advantageously, the adhesive material is high temperature
silicone.

[0030]
It is advantageous if an adhesive layer is adhesively connected to
a holding element, by means of which the inlet window is fixed to
the pressure vessel. The retaining element then does not have to
be connected directly to the entrance window - as is the case with
the glass flange known from the prior art as the retaining element
- but a non-rigid connection between the retaining element and the
entrance window can be formed.

[0031]
It is advantageous if the holding element is connected via a
clamping connection with the pressure vessel wall. For example,
can be arranged in a corresponding clamping element of the
clamping connection corresponding means for supplying detergent
and coolant in the interior of the pressure vessel. Such devices
are usually only a small amount of wear. The retaining element,
however, which is adhesively connected to the entrance window, at
least with respect to the adhesive layer is subject to high wear.
In an exchange then does not have to be replaced with its coolant
devices the entire clamping element, but it is sufficient to
replace only the retaining element.

[0032]
In a variant of one embodiment, an adhesive layer facing the
interior of the pressure vessel is connected to the inlet window.

[0033]
It is advantageous if the holding element is connected in the
interior of the pressure vessel with this.

[0034]
In another embodiment, an adhesive layer is connected to the
entrance window facing an exterior space. This has the advantage
that the adhesive layer is not acted upon by the working medium
and the like in the interior of the pressure vessel and is more
easily accessible for maintenance or replacement. However, it can
also be provided that, for example, in a storage bed, an adhesive
layer is arranged both in the interior and exterior space.

[0035]
In an advantageous variant of an embodiment, the holding element
outside the interior of the pressure vessel is connected thereto.
In this way, an adhesive layer for fixing the entrance window to
the pressure vessel can be formed, which is arranged outside of
the interior, so as to reduce the temperature of the adhesive
layer and to prevent the Arbeitsmediumbeaufschlagung.

[0036]
It is particularly advantageous if the storage bed material is an
adhesive material, so that the storage bed also provides for
fixing the entrance window to the pressure vessel.

[0037]
It is advantageous if a holding element, by means of which the
inlet window is connected to the pressure vessel via an adhesive
layer, has an undercut space for receiving adhesive material. As a
result, a fixation between the inlet window and the holding
element and thus with respect to the pressure vessel can be
achieved, even if the adhesive layer decreases or fails in its
adhesive action, because through the undercut room can form a
positive connection between the holding element and adhesive
layer.

[0038]
It is favorable if an adhesive layer facing the interior of the
boiler has one or more interruptions in the direction of an
entrance window foot. This allows a pressure equalization between
an upper side and a lower side of the adhesive layer, so as to
reduce the force load of the adhesive layer.

[0039]
In order to increase the life of the adhesive layer, in particular
by reducing the temperature load, a heat radiation protection
device for an adhesive layer is provided according to the
invention. Infrared radiation from the interior of the pressure
vessel and in particular from an absorber forth and from the
coupling into the window in principle acts on the adhesive layer.
By a heat radiation protection device, this admission is at least
reduced. For example, a reflective layer or a reflective element
can be arranged on the adhesive layer so as to reduce the
radiation absorption by the adhesive layer and thus its heating.
For example, additionally or alternatively, a shield element can
be arranged above the adhesive layer in order to shield at least a
part of the heat radiation.

[0040]
It is advantageous if the shield element is arranged and designed
so that a pressure equalization between adhesive layer and shield
element with respect to an interior of the boiler is possible, so
that the shield element is not too heavily loaded with force.

[0041]
It is structurally favorable when the shield element is seated on
a clamping element, by means of which a retaining element is held
by clamping on the pressure vessel, wherein the adhesive layer is
connected to the retaining element.

[0042]
In a variant of one embodiment, the shield element is arranged as
a cover on the adhesive layer and in particular is designed to be
reflective in order to at least partially reflect back infrared
radiation and thus to reduce the absorption.

[0043]
To increase the service life, d. H. To increase maintenance
intervals, it is particularly advantageous if one or more coolant
channels are arranged in the pressure vessel wall in the region of
a Eintrittsfensterfußes.

As a result, the entrance window in the area of ??his foot can
then be cooled and, in particular, an adhesive layer can be cooled
in this area. In turn, the service life of the radiation receiver
according to the invention is increased because the life of the
adhesive layer is increased.

[0044]
Furthermore, it is particularly advantageous if a flushing device
for flushing the inlet window is provided on an inner surface
facing the interior of the boiler. In the operation of a radiation
receiver often the problem arises that water condenses at the foot
of the inlet window when the working medium is water
vapor-containing and the temperature in the region of the window
foot below the condensation temperature. This water condensation
has in particular the disturbing effect that an inner insulation
is soaked in the pressure vessel. By flushing the entrance window
on its inner surface (the pressurized side), water condensation at
the window in this area can be avoided.

[0045]
It is advantageous if the rinsing agent can be introduced into the
interior of the pressure vessel in the region of an entry window
foot, since the greatest risk of water condensation exists in this
area in particular.

[0046]
It is advantageous, when the rinsing agent is introduced into the
interior of the pressure vessel, that an adhesive layer, by means
of which the inlet window is fixed in the pressure vessel, is
coolable. The rinsing agent then acts simultaneously as a rinsing
agent and coolant, with which - also in addition - the adhesive
layer can cool, so as to increase their service life.

[0047]
It is advantageous if the rinsing agent is passed through a grid
to create a pressure loss and to effect a uniform flow profile and
thus to ensure a uniform distribution.

[0048]
In particular, to avoid water condensation, it is advantageous if
a flushing gas free of steam is used as the rinsing agent.

[0049]
Furthermore, it is favorable if a flushing device is provided for
flushing an outer surface of the inlet window facing the outer
space of the pressure vessel. This outer surface is the side of
the window opposite to the pressurized side. As a result, the
window, which is heavily thermally stressed by the coupled-in
radiation, can be cooled and also cleaned, for example by dust.

[0050]
It is advantageous if one or more coolant channels for supplying
coolant to the inlet window between an aperture insert and the
pressure vessel wall are arranged for this purpose. It can then be
a detergent or Lead coolant over the corresponding window area,
which can then escape through the aperture. As a result, the inlet
window can be actively cooled and, by suitable design of
corresponding outlet openings, it is possible to selectively blow
on locations that are particularly subject to thermal stress, such
as, for example, a vertex area of ??the entrance window. By a
suitable control and measurement, the detergent or Dose coolant
depending on the operating state of the radiation receiver to the
place of loading and loading amount to optimally cool the entrance
window.

[0051]
In particular, it is favorable if a nozzle, by means of which
coolant can be fed to the inlet window from the outside space, is
designed as a swirl nozzle in order to ensure a surface loading of
the inlet window.

[0052]
It is particularly advantageous if a front flange of the pressure
vessel, on which the inlet window is mounted, is bendable and, in
particular, elastic. When pressurizing the pressure vessel
experiences the pressure vessel wall (and thus the front flange) a
deflection, d. H. she can get deformed. If the face of the
entrance window is not flat, the front flange can adapt to the
entrance window due to its deformability. Although the uneven
stress distribution generated on its end face due to a non-planar
design of the entrance window is not remedied thereby, but the
differences between minimum values ??and maximum values ??are
reduced, ie. H. Voltage peaks are reduced because the front flange
can adapt. In turn, the risk of breakage of the entrance window is
substantially reduced, since just high voltage spikes are avoided.

[0053]
Due to the deformability of the front flange is a change in shape
of the same when pressurized. With appropriate design of the front
flange, this shape change can be compensated. In particular, it is
advantageous if a bearing surface of the front flange for the
inlet window has a tendency in the unloaded state in the radial
direction. With appropriate design then a support surface is the
entrance window in the operating state just.

[0054]
It is advantageous if the front flange is formed so that the ratio
of its deflection to the diameter based on the operating condition
of the pressure vessel at least 2. 10 <-4> is. For example,
with an internal pressure of 15 bar and a bowl diameter of 1 m,
the deflection should be of the order of 0.3 mm or more so as to
reduce stress peaks in the bearing of the entrance window on the
front flange in the entrance window.

[0055]
It is particularly advantageous if the entrance window is
dome-shaped, so that a high compressive strength is ensured.

[0056]
In an advantageous variant of an embodiment, an insert element is
arranged in an aperture of the entry window. The insert element
then serves in particular to protect the pressure vessel wall and
the bearing device from the radiation. Conveniently in the insert
element thereby formed as a secondary concentrator to couple
radiation into the interior of the pressure vessel, which is
reflected at the insert element.

[0057]
It is structurally favorable when the insert element is
circumferentially formed as a polygon, for example, as eighteen.

[0058]
The following description is used in conjunction with the drawings
for further explanation of embodiments of the invention. Show it:

[0059] Fig. 1 is a schematic sectional view of a radiation
receiver according to the invention; [0060] FIG. 2 shows a first embodiment of a bearing device
according to the invention in a detail view of the region A
according to FIG. 1; FIG. [0061] Fig. 3 is a detail view of a second embodiment of a
storage device according to the invention and [0062] Fig. 4 is a detail view of a third embodiment of a storage
device according to the invention.

[0063]
An embodiment of a radiation receiver according to the invention,
which is designated in Fig. 1 as a whole with 10, comprises a
pressure vessel 12 through which a working medium for receiving
energy from solar radiation can be guided under pressure.

[0064]
The pressure vessel 12 comprises a pressure vessel wall as a front
flange 14; the pressure vessel 12 is positioned so that the front
flange 14 faces concentrated solar radiation 16. The solar
radiation 16 is coupled via a mounted on the front flange 14
entrance window 18 in an interior 20 of the pressure vessel 12.
The interior 20 is formed within the front flange 14 and of
pressure vessel walls 22.

[0065]
The entrance window 18 is dome-shaped with an entrance window axis
24, with respect to which the entrance window 18 is rotationally
symmetrical. The entrance window axis 24 is oriented perpendicular
to the front flange 14, and preferably, the pressure vessel 12 and
in particular the interior 20 of the pressure vessel 12 is
rotationally symmetrical with respect to this axis 24 is formed. A
vertex 26 of the entrance window 18 is facing the interior 20
behind an aperture 28 in the front flange 14th Solar radiation 16
passes through the aperture 28 to and through the entrance window
18, which is in particular a quartz glass window.

[0066]
In the aperture 28, an aperture insert 30 is inserted so that an
end face 32 of the front flange 14 is covered. For this purpose,
the aperture insert part 30 has a frustoconical ring element 32,
wherein the (imaginary) cone tip is set back relative to the front
flange 14 in the direction of the interior 20 of the pressure
vessel 12. Furthermore, the aperture insert part 30 comprises an
example cylindrical portion 34, which lies around a foot portion
36 of the entrance window 18 and is thus arranged behind the
aperture 28. The aperture insert 30 serves to protect the front
flange 14 from solar radiation. In particular, the aperture insert
part 30 is designed as a secondary concentrator in order to
concentrate radiation reflected at the aperture insert part 30
through the entrance window 18 into the interior 20 of the
pressure vessel 12.

[0067]
The aperture insert 30 is not annular in cross-section in a
variant of an embodiment, but has the shape of a polygon such as a
achtzehnecks circumferentially.

[0068]
In the interior 20 of the pressure vessel 12, a designated as a
whole with 38 absorber is arranged, which can be acted upon via
the entrance window 18 by the solar radiation 16 and can be
heated. By the absorber 38, the working medium for energy
absorption is feasible, d. H. the working fluid heats up during
the guide through the absorber 38. The absorber 38 is accordingly
a volumetric absorber, i. H. the absorber absorbs the radiation
substantially over its entire volume. For this purpose, the
absorber 38 is made for example of a porous material or wire mesh.
The radiation receiver is therefore a volumetric radiation
receiver.

[0069]
The absorber 38 includes an inlet absorber 40 through which an
inlet stream is led to preheat. For this purpose, an inner jacket
42 is disposed in the interior 20 of the pressure vessel 12, which
is formed substantially parallel to the pressure vessel wall 22
and between the pressure vessel wall 22 and an inlet stream 44 is
feasible. In the interior 20 of the pressure vessel 12, a flow
space 46 is formed around the inlet window 18, through which the
working fluid flows to an outlet absorber 50 after flowing through
an inlet flow space 48 and flow through the inlet absorber 40. The
flow space 46 is thereby formed between the inlet absorber 40, the
inlet window 18 and the outlet absorber 50.

[0070]
The Auslaßabsorber 50 is arranged with respect to the entrance
window 18 and formed so that a high radiation power is absorbed
and a high volume flow through the outlet absorber 50 is feasible,
so that the working fluid can absorb a high heat output.

[0071]
An outlet stream 52 is removed from the interior 20 after
absorption of heat in the absorber 38.

[0072]
In the interior 20 of the pressure vessel 12, in the variant of an
embodiment of a pressure vessel 12 according to the invention
shown in FIG. 1, a further inner jacket 54 is arranged which has a
wall 56 which is parallel spaced from a corresponding wall 58 of
the inner jacket 42. Characterized a particular annular opening 60
is formed in the interior 20 of the pressure vessel 12 through
which a partial stream 62 of the outlet stream 52 via a return
space 64 in the inlet flow space 48 is traceable.

[0073]
By such a partial recirculation of an outlet flow from the
Auslaßstromführung to an inlet flow in the inlet flow, a
Durchgangsmassestrom the working medium flow can be increased so
as to reduce in particular fluctuations in a mass flow
distribution of a fluid flow in the absorber 38 and thereby
possibly occurring temperature peaks, which can cause instability.
Such a device and a corresponding method is described in DE 197 10
986 A1, which is hereby expressly incorporated by reference.

[0074]
Between the pressure vessel wall 22, the front flange 14 and the
inlet flow space 48, a thermal inner insulation 66 is arranged,
which comprises at least one layer of insulating material and in
particular includes pressure compensation means for pressure
equalization between the insulating material and a boiler
interior, which are arranged over a large area relative to a layer
surface of the insulating material. Such an insulation system is
described in DE 197 13 598 A1, which is hereby incorporated by
reference.

[0075]
In particular, it may be provided that the insulation system of
the inner insulation 66 has a filter which is arranged between the
pressure compensation means and a layer surface of the insulating
material and serves to retain Dämmaterialpartikeln.

[0076]
The entrance window 18 is mounted on the front flange 14 by means
of a bearing device. In a first embodiment of a bearing device
according to the invention, which is designated as a whole by 68
in Fig. 2,the front flange 14 on its end face 32 has an annular
recess 70 through which a support surface 72 is formed, on which
the entrance window 18 with an end face 74 rests. Between the end
face 74 while a seal 76 is arranged, which serves to seal the
interior 20 of the pressure vessel 12 relative to the outer space.
The seal 76 is in particular a multi-layer seal with layers of
precompressed graphite and intermediate layers of thin stainless
steel foils. The graphite serves to achieve a high temperature
resistance and the intermediate layers to achieve a high
mechanical strength.

[0077]
Between the seal 76 and the bearing surface 72 of the front flange
14, a sliding layer 78 is arranged, which has a reduced
coefficient of sliding friction, so that the inner window 18 with
the seal 76 on the sliding layer transversely to the entrance
window axis 24 is movable and this movement takes place on the
sliding layer 78 itself , In particular, the sliding friction
coefficient for the sliding friction of the entrance window 18
with the seal 76 on the sliding layer 78 must be lower than the
sliding friction coefficient for the sliding friction of the
entrance window 18 on the seal 76 or for the sliding movement of
sealing layers relative to each other. A typical value for the
coefficient of sliding friction of quartz glass on graphite is
0.1. Preferably, then, the sliding friction coefficient of the
sliding layer 78 is of the order of, for example,

0.05. It is then achieved that the relative movement of the
entrance window 18 takes place with respect to the front flange 14
via sliding on the sliding layer 78, d. H. takes place at the
location defined by the sliding layer 78.In particular, by the
destruction of the seal 76 is avoided, for example by separation.

[0078]
By the movement of the entrance window 18 relative to the front
flange 14, mechanical stresses in the entrance window 18 can be
reduced, as they can arise in particular by the pressurization of
the entrance window 18 and by the temperature of the inlet window
18 and the front flange 14.

[0079]
In a variant of one embodiment, the sliding layer 78 is formed by
applying a lubricant to the support surface 72 in a defined area.
As a lubricant, for example, high-viscosity silicone grease can be
used. In addition to a good sealing effect, this material also has
good temperature, pressure, weather and chemical resistance as
well as a long service life under operational use conditions. In
addition, high-viscosity silicone grease is free of alkali metals
and alkaline earth metals. As a result, the risk of contamination
of the entrance window 18 is avoided.

[0080]
It can also be provided a depot for the lubricant to get at
Gleitmittelverlusten the lubricity of the sliding layer 78 by
appropriate lubricant subsequent delivery (not shown in FIG. 2).

[0081]
In an alternative variant of an embodiment, the front flange 14 is
provided at its bearing surface 72 with a corresponding
low-friction coating to form the sliding layer 78, by which the
sliding friction coefficient between the inlet window and the seal
76 with respect to sliding on the sliding layer 78 relative to the
sliding friction coefficient between the inlet window 18 and Seal
76 with respect to sliding on the seal 76 is reduced.

[0082]
In order to be able to monitor a failure of the sliding layer 78,
a tension measuring device 80 is arranged in the foot region 36,
by means of which mechanical stresses in the inlet window 18 can
be measured in this region, in order in particular to be able to
indicate a failure of the sliding layer 78 as a defined sliding
surface. In particular, the stress measuring device 80 includes
one or more strain gauges. Such a strain gauge indicates strain
and thus the presence of mechanical stresses in the region where
the strain gauge is seated at the entrance window 18.

[0083]
At one of the interior 20 of the pressure vessel 12 facing inner
wall 82 of the front flange 14 is seated in particular positively
connected, for example by screw 84, a clamping ring 86th By this
clamping ring 86, a retaining ring 88 is clamped to the front
flange 14 in the interior 20 of the pressure vessel 12 is held.
The retaining ring 88 serves as a holding element for the entrance
window 18 and has a cross-sectionally L-shaped configuration,
wherein a first wing 90 between the clamping ring 86 and the inner
wall 82 of the front flange 14 is clamped and a second wing 92 in
the recess 70 the Entrance window 18 is arranged facing.

[0084]
Between the entrance window 18 and the second wing 92 sits an
adhesive layer 94 so that the entrance window 18 is fixed by this
adhesive layer on the front flange 14. The adhesive material of
the adhesive layer 94 is a highly elastic adhesive material, such
as high-temperature silicone, so that the mobility of the entrance
window 98 is retained on the sliding layer 78 in particular
transversely to the entrance window axis 24 and also by the
adhesive material of the adhesive layer 94 no significant forces
on the entrance window 18 exercised.

[0085]
In the variant of an embodiment shown in Fig. 2, the retaining
ring 88 has been glued before introduction of the entrance window
18 into the recess 70 in the manufacture of the radiation receiver
10 according to the invention so that when clamping the retaining
ring 88, the adhesive layer 94 is slightly down in the direction
of Support surface 72 is pressed. This results in a shear
deformation in the adhesive layer 94, so that even without
pressurization of the interior 20 of the pressure vessel 12, a
contact pressure of the entrance window 18 acts on the support
surface 72.

[0086]
Preferably, the adhesive layer 94 facing second wing 92 of the
retaining ring 88 has an undercut 96, which is formed for example
as an annular groove. This serves to increase the contact area
between the adhesive layer 94 and the retaining ring 88. In
addition, thereby a kind of positive connection between the
adhesive layer 94 and the retaining ring 88 is made so that even
with loss of adhesive contact between the adhesive layer 94 and
the second wing 92 of the retaining ring 88, the entrance window
18 remains fixed to the front flange 14.

[0087]
In the recess 70, a cavity 98 is formed between the entrance
window 18, the adhesive layer 94 and the retaining ring 88. To
allow pressure equalization of the interior space 20 with this
cavity 98, the adhesive layer 94 is circumferentially intermittent
with respect to the entrance window axis 24 substantially parallel
to that axis (not visible in FIG. 2).

[0088]
To protect the adhesive layer 94 from heat radiation from the
interior 20 of the pressure vessel 12, a heat radiation protection
device is provided. For example, this may be a highly reflective
shielding element arranged on the surface of the adhesive layer 94
facing the interior 20 or a ceramic cord. In the embodiment shown
in Fig. 2, the clamping ring 86 has a nose-shaped shield member
100, which extends so far to the entrance window 18 that still a
pressure equalization between the interior 20 of the pressure
vessel 12 and the adhesive layer 94 is made possible.

[0089]
According to the invention, a flushing device 204 is provided, by
means of which the inlet window 18 faces the interior 20 of the
pressure vessel 12 (pressurized side) and can be formed on the
inlet window 18

to form a flushing film for cooling the entrance window 18. To go
through the front flange 14 feed channels 206, which are continued
in the clamping ring 86. In the clamping ring 86 corresponding
transverse

channels 208 are then arranged, which open into a distribution
space 210. At the distributor space 210 sits a grid 212 for
swirling the rinsing agent at the exit from the distributor space
210. Through a gap 214 between the shield element 100 and the
entrance window 18, the detergent reaches the interior 20. A
surface 216 of the inner insulation 66 is arranged so that the
entry of the detergent into the interior 20 of the pressure vessel
12 is not hindered.

[0090]
In an alternative embodiment (not shown in the drawing) supply
channels for detergent in the cavity 98 and the detergent can pass
through interruptions in the adhesive layer 94 in the interior 20
of the pressure vessel 12 pass.

[0091]
As rinsing agent in particular a steam-free purge gas is used. In
particular, the purge gas is conducted over the adhesive layer 94
or through the adhesive layer 94 so that it is actively cooled.

[0092]
Furthermore, a flushing device 218 is provided for flushing a
surface of the entrance window 18 facing the exterior. For this
purpose, supply channels 220 are arranged between the aperture
insert part 30 and the end face 32 of the front flange 14, which
continue into a foot region 36 of the entry window 18. A feed
channel 220 opens via a nozzle 222 in a space behind the aperture
28th For example, a supply channel 220 may be formed as an annular
channel or circumferentially distributed tubes or tubes or the
like may be provided. Via the flushing device 218, the inlet
window 18 can be acted upon with rinsing agent in the space 224
(FIG. 1) which is open to the atmosphere, and in particular
thermally particularly stressed areas of the inlet window can be
specifically blown and thus cooled separately. It can be cleaned
in this way, the entrance window 18 of impurities such as dust.

[0093]
Conveniently, it is provided that the front flange 14 is formed
elastically deformable at least in the region of the support
surface 72. In this way, unevenness of this support surface 72 can
be compensated.

When not level bearing surface, the problem arises that in the
entrance window 18 voltage spikes can be present. By ensuring an
elastic deformability of the front flange 14, such voltage peaks
can be reduced and thus the risk of breakage for the entrance
window 18 can be reduced.

[0094]
It is particularly provided that the support surface 72 has a
slight inclination in the radial direction transverse to the
entrance window axis 24 in the pressureless state of the pressure
vessel 12. When pressure load in the operating state with an
appropriate design of such an inclined support surface 72 then
this, when an elastic deformation occurs, again substantially
perpendicular to the entrance window axis 24th

[0095]
In particular, it is provided that in the operating state of the
radiation receiver 10, the deflection of the front flange 14 at
the bearing surface is at least greater than 2. 10 <-4> the
boiler diameter. For example, with an internal pressure of 15 bar
and a bowl diameter of 1 m, the deflection should be more than 0.3
mm.

[0096]
The radiation receiver 10 according to the invention functions as
follows:

[0097]
Highly concentrated solar radiation 16 is coupled via the entrance
window 18 into the interior 20 of the pressure vessel 12 and heats
the absorber 38 there. The working medium introduced via the flow
space 46 heats up and passes through the inlet absorber 40, is
thereby preheated and then passes through the outlet absorber 50
for the final heating. In the variant shown in FIG. 1, a partial
flow 62 is branched off and returned by an outlet flow 52.

[0098]
By pressurizing the working medium, a window foot diameter of the
entrance window 18 is reduced. Due to the heating, the front
flange 14 expands. Furthermore, the front flange 14 warps under
pressure and under heating, so that the parallelism between the
end face 74 of the entrance window 18 and the support surface 72
is deteriorated. This creates mechanical stresses and in
particular bending stresses in the entrance window 18 and in
particular in the foot region 36 there.

[0099]
According to the invention, these stresses are at least partially
degradable in that a movement of the entrance window 18 on the
sliding layer 78 is made possible. In particular, the invention
ensures that the entrance window 18 does not slide on the seal 76,
but just on the defined location of the sliding layer 78th

[0100]
About the flushing device 204, the pressurized side of the inlet
window 18 can be rinsed and cooled and the flushing device 280,
the atmosphere-facing side of the entrance window 18 can be
flushed and cooled. The adhesive layer 94 can be cooled via the
coolant channel 202, which can also be cooled by means of the
flushing device 204.

[0101]
A second embodiment of a bearing device according to the
invention, which is designated in FIG. 3 as a whole by 226, is
basically the same as described above. The same components
therefore bear the same reference numerals. A retaining ring 228
as a holding element for the inlet window 18 is clamped on the
inner wall 82 of the front flange 14 is held. The retaining ring
228 has an annular trough portion 230, on which radially outwardly
with respect to the entrance window axis 24, a tab 232 is seated.
By means of this tab 232, the retaining ring 228 between the
clamping ring 86 and the inner wall 82 of the front flange 14 is
clamped. For fluid-tight sealing, a seal 234, for example in the
form of an O-ring, is arranged between the tab 232 and the inner
wall 82.

[0102]
The trough portion 230 of the retaining ring 228 is positioned in
the recess 70 of the front flange 14. The trough portion 230
itself has an annular groove 236 which serves to form a storage
bed 238 for supporting the entrance window 18 in the retaining
ring 228. For this purpose, a bearing bed material 240 is arranged
in the groove 236 between the entrance window 18 and the retaining
ring 228, which is deformable and in particular elastically
deformable to allow movement of the entrance window 18 in the
bearing bed 238 transverse to the entrance window axis 24 relative
to the front flange 14. Further, bedding material 240 is disposed
on a floor 242 of the channel 236 so that the entrance window 18
rests on bedding material 240.

[0103]
The bedding material is a material which has a high (compressive)
modulus of elasticity parallel to the entrance window axis 24 and
a low shear modulus transverse thereto. In particular, the bedding
material 240 has an adhesive effect to provide additional adhesive
fixation of the entrance window 18 to the retainer ring 228. To
produce a positive connection between the bed material 240 and the
trough portion 230 of this is provided with an example,
circumferential undercut 244, can penetrate into the bed material.

[0104]
For example, high-temperature silicone 240 is used as the bearing
bed material.

[0105]
In order to prevent the bedding material 240 from escaping and in
particular extruding out of the channel 236, it may be provided
that a cover, for example in the form of a ring, is arranged above
the fill level of the bedding material 240 in the channel 236 (not
shown in the figure). ,

[0106]
The elastic bearing bed material 240 assumes a holding function
for the entrance window 18 in the retaining ring 228, d. H. fixes
the entrance window, allows movements of the entrance window 18 in
particular transversely to the entrance window axis 24 so as to be
able to break down shear stresses in the entrance window 18, seals
the interior 20 of the pressure vessel 12 from the outside and due
to its elastic deformability is uneven at the bottom 242 and the
end face 74 of the entrance window 18, so that voltage peaks in
the entrance window 18, which may be caused by such bumps, are
largely avoided or at least reduced and partially reduced. By the
storage of the entrance window 18 in the storage bed 238, the
tightness of the interior 20 with respect to the exterior space is
ensured even in the unpressurized state of the pressure vessel 12.

[0107]
To protect against heat radiation from the interior 20 of the
pressure vessel 12, as described in connection with FIG. 2,
shielding elements for the bearing bed material 240 may be
arranged.

[0108]
Incidentally, the bearing device 226 functions as the bearing
device 68 described in connection with FIG. 2.

[0109]
In a third embodiment of a bearing device according to the
invention, which is designated in FIG. 4 as a whole by 246, a
distributor ring 248 is positively connected in the interior 20 of
the pressure vessel 12 to the front flange 14. This distribution
ring 248 is substantially the same structure as the clamping ring
86 according to the first and the second embodiment of a bearing
device according to the invention and serves to distribute the
detergent, but it does not act as a clamping device for a holding
element.

[0110]
In the bearing device 246 according to the invention, a holding
element 250 is provided for fixing the inlet window 18, which is
connected to the front flange 14 outside the interior 20 of the
pressure vessel 12.

In a variant of an embodiment, the holding element 250 comprises
an annular portion 252, for example, which is arranged in the
space 224. This section is followed by a widening annular portion
254, which is

adapted to the end face 32 of the front flange 14 and adjoins
this. This section 240 is followed by an annular strap section
256, which rests against an outer wall 258 of the front flange 14
and which is connected to the front flange 14 in a form-fitting
manner, for example by means of a screw connection 260. As a
result, the holding element 250 is held on the front flange 14. It
can be provided that the portion 254 is connected to the end face
32, for example by gluing or by a positive connection.

[0111]
The annular portions 252, 254 and 256 are formed, for example, by
spaced tabs which are bendable. During assembly, the entrance
window 18 can then be placed on the front flange 14, and for the
final positioning and in particular fixation of the entrance
window 18, the tabs of the sections 252, 254 and 256 are bent into
their holding position.

[0112]
In the recess 70 of the front flange 14, the inlet window 18 is
mounted on the seal 76 on a sliding layer 78, as has already been
described in connection with the first embodiment of a storage
device according to the invention shown in FIG.

[0113]
Between the retaining ring 228 and an outer surface 262 of the
entrance window 18, which faces the outer space, sits an adhesive
layer 264 for fixing the entrance window 18 to the support member
250th

The adhesive layer 264 thus sits in the outer space and not as in
the storage device 68 in the interior 20 of the pressure vessel
12th This arrangement of the adhesive layer 264, the accessibility
to this layer from the outside is possible and it is avoided that
the adhesive layer 264 comes into contact with the working fluid,
which is passed through the interior 20 of the pressure vessel 12.
Also, the thermal stress of the adhesive layer 264 is reduced.

[0114
By a shield member 266 such as a ceramic cord, the adhesive layer
264 is shielded from heat radiation, so as to protect them from
overheating.

[0115]
The retaining member 250 may also include a plurality of
circumferentially spaced retaining plates. In a variant of one
embodiment, the retaining element 250 is integrated into the
aperture insert part 30.

[0116]
Otherwise, the bearing device 246 according to the invention
functions as already described above in connection with the
further embodiments of a bearing device according to the
invention.